Method for making semi-permeable polymer membranes
AssigneeCorning Incorporate
InventorsKishor P. Gadkaree, Leroy S. Hersh
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Abstract
A method for making a semi-permeable microporous polymer sheet, useful as a separation membrane or the like, including extruding a melt-blended mixture of a high-temperature thermoplastic polymer and a leachable glass to form sheet and then leaching the glass from the sheet to leave a microporous relict polymer network, wherein the permeability of the sheet is improved by plasma-etching the surface of the sheet before or after leaching. Hydrophilic or hydrophobic porous membranes may be provided.
Claims11
A method for making a semi-permeable microporous polymer sheet having an intercommunicating pore structure which comprises the steps of blending a batch mixture of a thermoplastic polymer and a finely divided leachable glass to form a two-phase glass-polymer blend material, extruding the glass-polymer blend material through a die to form a sheet having a sheet surface and comprising a continuous polymer network and an intercommunicating glass phase, and thereafter leaching the intercommunicating glass phase from the sheet without disruption of the polymer network, wherein:
- prior to or subsequent to leaching, the sheet surface is exposed to a plasma of an energy at least sufficient to etch thermoplastic polymer from the sheet surface, for a time at least sufficient to increase the area of leachable glass or intercommunicating pore structure exposed at the sheet surface, thus to provide a microporous polymer sheet having an intercommunicating pore structure.
Dependencies are inferred from the claim text.